Control rod alloy containing noble metal additions



United States Patent CONTROL ROD ALLOY CONTAINING NOBLE METAL ADDITIONS William K. Anderson and William E. Ray, Schenectady,

N.Y., assignors to the United States of America as represented by the United States Atomic Energy Commission No Drawing. Application December 10, 1957 Serial No. 701,937

12 Claims. (Cl. 75-173) This invention relates in general to alloys suitable for use in the fabrication of control rods for neutronic reactors, and more specifically to silver base alloys suitable for such applications.

It is an object of this invention to provide an alloy composition suitable for use in fabricating control rods for neutronic reactors.

It is a further object of this invention to provide an alloy composition suitable for use in control rods for neutronic reactors, which possesses superior structural strength properties.

The alloys of this invention are essentially improvements of an already existing alloy, which is the subject of copending application Ser. No. 688,995, filed October 8, 1957. This alloy is known to have nuclear properties which make it quite suitable for use as a neutronic reactor control rod material. The already know alloy consists essentially of from 0 to percent of cadmium, from 2 to weight percent of indium and from 65 to 85 weight percent silver, and while this alloy has a proven nuclear worth, it lacks structural strength characteristics to an extent sufficient to restrict its use in some applications.

It has been found that this shortcoming of the original cadmium-indium-silver alloy may be overcome through the addition to the basic alloy of a noble metal selected from the group consisting of platinum, ruthenium, rhodium, osmium, and palladium in amounts from about 0.5 weight percent to about 1.5 weight percent. This can be seen more clearly by reference to the attached table. 5 weight 2,935,401 Patented May 3, 11960 Any conventional method of preparation may be employed in producing the alloy compositions of this invention. The alloy can be easily prepared by placing in a graphite crucible the desired constituents. The components may then be melted by means of induction heating apparatus or by any other suitable means. To prevent oxidation of the molten alloy, a protective cover of calcined coke pellets may be placed on the surface of the melt, and after melting, the alloy may be cast by any convenient method.

It is not intended that this invention be limited in any way except by the scope of the appended claims.

We claim:

1. An alloy adapted for use as a neutronic reactor control rod material consisting of from 0.5 weight percent to about 1.5 weight percent of a noble metal selected from the group consisting of platinum, ruthenium, rhodium, osmium, and palladium, up to 10 weight percent of cadmium, from 2 weight percent to 20 weight percent indium, the balance being silver.

2. A control rod member for use in neutronic reactors consisting of an alloy falling within the compositions of claim 1.

3. An alloy adapted for use as a neutronic reactor control rod material consisting of about 1 weight percent platinum, about 5 weight percent cadmium, about 15 weight percent indium, the balance being silver.

4. A control rod member for use in neutronic reactors consisting of the alloy of claim 3.

5. An alloy adapted for use as a neutronic reactor controd rod material consisting of about 1 weight percent ruthenium, about 5 weight percent cadmium, about 15 weight percent indium, the balance being silver.

6. A control rod member for use in neutronic reactors consisting of the alloy of claim 5.

7. An alloy adapted for use as a neutronic reactor control rod material consisting of about 1 Weight percent rhodium, about 5 weight percent cadmium, and 15 weight percent indium, the balance being silver.

8. A control rod member for use in neutronic reac tors consisting of the alloy of claim 7.

9. An alloy adapted for use as a neutronic reactor control rod material consisting of about 1 weight percent osmium, about 5 weight percent cadmium, about 15 percent indium, the balance being silver.

Data showing mechanical properties of modified Cd- In-Ag alloys (additions of the indicated percentage of fourth metal, as shown, to the basic 5% Cd15% In% Ag alloy) Sample 0.2% Offset, Ult. Str., Percent Percent Hard- Composition Number Yield Str., lbs/in. Elong. Rednct. ness, Temp.

lbs/in. of area Rr Base Alloy 1 11, 760 44, 250 78. 2 57. 3 49.1 Rm. (0d 5 w/o, In 15 w/o, Ag 2 11,690 41, 590 71. 8 59. 5 49. 7 Rm. balance.) 3 11, 910 40, 670 75. 0 61. 4 49. 9 Rm.

4 7, 400 ,360 60.5 52.9 600 F 5, 900 37, 400 84. 4 59. 7 38 Rm. 0.1 wt. Percent Pt. 9, 300 38, 700 81. 2 61.6 45 Rm. 0.5 wt. Percent Pt. 14, 900 500 75. 0 57. 8 52 Rm. 1.0 wt. Percent Pt. 1 16, 200 41, 65. 6 51. 0 64 Rm. 1.0 wt. Percent Pt--- 2 15, 200 50. 0 44. 9 64.1 600 F. 1.0 wt. Percent Pt--. 3 11,800 14, 750 41. 5 63. 5 600 F. 1.0 wt. Percent Pd- 1 20, 490 43, 800 68. 8 52. 2 60. 9 Rm. 1.0 wt. Percent; Pd. 2 20, 390 43, 790 75.0 52. 9 55. 9 Rm. 1.0 wt. Percent Ru 1 18, 990 38, 690 75.0 59. 4 37. 9 Rm. 1.0 wt. Percent Ru- 2 10, 930 12, 890 94.1 37. 5 600 F 1.0 wt. Percent Ru.. 3 18, 660 38, 75.0 57.1 36. 9 Rm. 1.0 wt. Percent Ru 4 11, 12, 680 59. 4 62. 4 48. 9 600 F 1.0 wt. Percent Ru 5 21, 010 39, 760 65.6 48. 8 50. 9 Rm. 1.0 wt. Percent Ru 6 11, 500 13, 240 53. 2 45. 4 54. 4 600 F 1.0 wt. Percent 0s 1 21, 730 40, 170 56. 2 46. 3 50. 5 Rm. 1.0 wt. Percent Os 2 21, 910 39,360 62. 4 47. 7 54. 2 Rm. 1.0 wt. Percent Rh. 1 26, 610 44,070 59.4 56.1 73. 9 Rm. 1.0 wt. Percent; Rh 2 26, 700 44, 170 62. 4 58. 7 70. 7 Rm. 1.0 wt. Percent Rh 3 26, 650 62. 4 67. 3 74. 8 Rm. 1.0 wt. Percent Rh 4 11, 560 13, 760 59. 4 73. 4 74.9 600 1.0 wt. Percent Rh 5 11,150 12,840 87.6 89. 4 75.4 600 F 1.0 wt. Percent Rh 6 10, 880 12, 260 65. 6- 73. 9 77. 0 600 F.

V 3 10. A control rod member for use in neutronic reactors consisting of the alloy of claim 9.

' 11. An alloy adapted for use as a neutronie reactor control rod material consisting of about 1 weight percent palladium, about 5 weight percent cadmium, about 15 weight percent indium, the balance being silver.

12. A control rod member for use in neutronic reactors consisting of the alloy of claim 11.

References Cited in e file of this patent UNlTED STATES PATENTS Henzel et 211.7". May 9, 1939 OTHER REFERENCES Technical Progress Review, Reactor Core Materials, vol. 1, No. 1, March 1958. (Pages 23 and 26 relied on.) 

1. AN ALLOY ADAPTED FOR USE AS A NEUTRONIC REACTOR CONTROL ROD MATERIAL CONSISTING OF FROM 0.5 WEIGHT PERCENT TO ABOUT 1.5 WEIGHT PERCENT OF A NOBLE METAL SELECTED FROM THE GROUP CONSISTING OF PLATINIUM, RUTHENIUM, RHODIUM, OSMIUM, AND PALLADIUM, UP TO 10 WEIGHT PERCENT OF CADMIUM, FROM 2 WEIGHT PERCENT TO 20 WEIGHT PERCENT INDIUM, THE BALANCE BEING SILVER. 